The present invention is directed to bicycles and, more particularly, to a bicycle disk brake apparatus.
Conventional bicycle disk brake devices comprise a disk rotor that rotates with the bicycle wheel, and calipers with brake pads that frictionally contact the disk rotor to slow or stop the wheel. The disk rotor may be a metal member that comprises a mounting member and a ring-shaped rotor member fixed to the mounting member, wherein the mounting member is structured to be mounted to the bicycle wheel hub. Since bicycles are propelled by human power, reducing the weight of the bicycle components is an important objective of many bicycle manufacturers. This includes reducing the weight of disk brake devices. On the other hand, it is also desirable to resist rotor wear caused by friction with the brake pads while providing proper heat dissipation.
One example of a conventional disk rotor that is lightweight and has good heat dissipation and wear resistance is disclosed in Japanese Unexamined Patent Publication Number 1-153826. That disk rotor comprises a stainless steel rotor braking face member joined by a metal interlayer to a rotor main body consisting of an aluminum alloy. Using aluminum for the rotor main body reduces weight and provides greater heat dissipation compared to rotors fabricated from stainless steel. To construct such rotors, the side of the braking face member that contacts the rotor main body is plated with nickel or the like, and then the braking face member is pressure welded to the rotor main body by holding the braking face member against the rotor main body for several hours at an elevated temperature and pressure. As a result, the rotor main body and braking face member are joined together, with an interlayer of a nickel aluminum metal formed between them. However, such rotors suffer from separation of the braking face member from the rotor main body despite the metal interlayer between them.